We have characterized a lung tumor associated antigen recognized by a monoclonal antibody, 503-D8, that was raised against a human lung adenocarcinoma cell line. Preliminary solid phase serological screening against glutaraldehyde-fixed tissue culture cell lines showed strong reaction with lung adenocarcinoma, large cell carcinoma and squamous cell carcinoma of the lung and little or no reactivity against small cell carcinoma of the lung. No reactivity was found against tumor cell lines of liver, kidney, gastric, or lymphoid origin and only a low degree of activity was noted when melanoma cells were examined. It is being characterized in terms of molecular weight, sub-unit size, nature of association of the antigenic moiety and the degree of glycosylation. Preliminary thin layer chromatography (TLC) studies on a partially purified glycolipid fraction from a human breast tumor cell line reveal the presence of a ganglioside that it is absent from similar preparation from a non-tumorigenic breast cell line. A human transforming growth factor (TGF) found only in cancer patients' urine has been partially purified and characterized with respect to urogastrone and competitive binding to receptors for epidermal growth factor.